insert_tags

Insert XML-style region tags at a fixed position in a sequence, creating a named segment that downstream operations can target by name. start and stop are 0-based indices into the underlying (non-tag) characters. Omitting stop creates a zero-length point tag at start.

import poolparty as pp
pp.init()

Parameters

Parameter	Type	Default	Description
`pool`	`Pool \| str`	(required)	The Pool to insert tags into. Can also be a plain sequence string.
`region_name`	`str`	(required)	Name for the region (e.g. `'cre'`, `'orf'`).
`start`	`int`	(required)	0-based start index, counting only non-tag characters.
`stop`	`int \| None`	`None`	Exclusive end index (non-tag characters). When `None` a zero-length point tag is created at `start`.
`iter_order`	`int \| None`	`None`	Enumeration order when combined with other pools.
`prefix`	`str \| None`	`None`	Prefix for the operation node name in the pool graph.

Note

Only the most commonly used parameters are shown above. For the full parameter list, see insert_tags() in the API Reference.

Examples

Tag a central region

Mark positions 4–12 of a 16-mer as the cre region.

wt     = pp.from_seq("AAAAATCGATCGTTTT")
tagged = pp.insert_tags(wt, "cre", start=4, stop=12)
tagged.print_library()

tagged: seq_length=16, num_states=1 AAAA<cre>ATCGATCG</cre>TTTT

Zero-length point tag (stop omitted)

Omit stop to place a self-closing tag at position 4 without enclosing any bases — useful as a landmark for replace_region().

wt    = pp.from_seq("AAAAATCGATCGTTTT")
point = pp.insert_tags(wt, "ins", start=4)
point.print_library()

point: seq_length=16, num_states=1 AAAA<ins/>ATCGATCGTTTT

Two non-overlapping regions in the same sequence

Apply insert_tags twice to define left and right regions.

wt    = pp.from_seq("AAAAATCGGGGGCCCTTTT")
step1 = pp.insert_tags(wt,    "left",  start=4,  stop=8)
step2 = pp.insert_tags(step1, "right", start=13, stop=17)
step2.print_library()

step2: seq_length=19, num_states=1 AAAA<left>ATCG</left>GGGGC<right>CCTT</right>TT

Chain into mutagenize to restrict mutations to the tagged region

Tag a region then mutagenize only that segment; the flanks stay intact. Use mode="sequential" for deterministic ordering of single mutants.

wt      = pp.from_seq("AAAAATCGATCGTTTT")
tagged  = pp.insert_tags(wt, "cre", start=4, stop=12)
mutants = pp.mutagenize(tagged, num_mutations=1, region="cre", mode="sequential")
mutants.print_library()

mutants: seq_length=16, num_states=24 AAAA<cre>CTCGATCG</cre>TTTT
AAAA<cre>GTCGATCG</cre>TTTT
AAAA<cre>TTCGATCG</cre>TTTT
AAAA<cre>AACGATCG</cre>TTTT
AAAA<cre>ACCGATCG</cre>TTTT ... (24 total)

See insert_tags().